Mcintosh Question- Looking for feedback

I was recently exposed to Mcintosh. I've owned Krell/Pass/Plinius/Parasound......I did get to hear the Mac amp I'm referring to.....but I didn't really get a chance to fully process the sonic signature. I just didn't have enough time. It did sound really good but it was in a top flight setup...and that was to be expected.

My question is:    I really like the Mac MA 7900. Its the 200 watt Integrated amp. How would you describe the sound from Mac solid state amps? What would you compare it too?

I'll be honest the sound was great....but the" visual eye candy effect" was stunning...absolutely the most visually pleasing gear I've seen personally.
I'm currently using the Parasound Halo Integrated. The Mac Ma 7900 would replace this. How much of an upgrade would this be ?

Any and all insight would be appreciated.  Also can someone give me the shortened version on why Mac has different speaker connections for different ohm speakers? I accustomed to wattage doubling in 4 ohms...any and all hel would be appreciated.

Thanks in advance,

As a former owner of a complete high end  McIntosh system, including the C1000 preamp, I can say that the sonic signature of Mac is generally rounded images and a warmer presentation. Until I heard D'Agostino, Plinius, Pass Labs, Wells Audio, Merrill Audio and others, I thought Mac was among the best. I believe it is now a step behind those brands and others. I cannot comment on Parasound as I've only heard them once in a system that sounded quite nice.  Despite all of the above, Mac ss for some reason, is a perfect partner for B&W speakers, especially the higher end speakers.  This is only my humble opinion.
 I especially like Plinius and Pass labs as they are both more forthright and transparent than Mac but not at all fatiguing. Krell made some excellent (and some not so excellent pieces). But since Dan D'agostino left, I haven't paid much attention to the brand.
As for the looks of Macs---I've always loved that look, but the price you pay is on the technology side and the sound side. 
Also can someone give me the shortened version on why Mac has different speaker connections for different ohm speakers? I accustomed to wattage doubling in 4 ohms.
Many of the McIntosh solid state amps are unusual in that they employ an autoformer (aka auto-transformer) at their outputs.  The rationale is basically that the output stage of the amp will then see essentially the same load when a 2 ohm load is connected to the 2 ohm tap as when a 4 ohm load is connected to the 4 ohm tap as when an 8 ohm load is connected to the 8 ohm tap.  And consequently the output stage will not have to supply the increased amount of current that would normally be drawn by a speaker having low impedance.

As you noted, with that approach the maximum power capability of the amp is the same in each of the three cases, as it is in the case of many tube amps which provide multiple taps on their output transformers.

What can be said about that approach?  Well, it's a design philosophy.  FWIW, I would neither be attracted to nor reject a McIntosh amplifier from consideration based on its use of that approach.

-- Al
I'm now convinced that one should look at the speakers and amplifiers as a single package. A top of the line McIntosh amp may sound too warm and boring with certain speakers and blow you away with another brand/model. Same with Krell. It may sound bright and dry with the wrong speakers. Pass Labs models appear to be a safe bet since they are known for their neutral sound. If I were to buy an amplifier that I could use as an anchor in my system that allowed me to do all my other (future) upgrades around it, I would buy one of the higher powered class A models from Pass Labs and call it the day.
I second tkalali thoughts regarding which speaker you use it with.  I own Klipsh LaScalas circa 1978.  With most every other I own ,several  including tube amps and integrated SS and tube they are dry and squwacky  (a new but accurate descriptor) , but with an old 50 watt SSmac, they sound pretty good.  It is just a symbiotic or synergistic phenomena.  I too think the sound is vague  and rounded in a general way.
Agree with Kalali and mechans, amps and speaks need a coherent match to sound best.  And it would be a luxury for most if we could buy both at the same time to ensure synergy.

I have had Mcintosh 501's SS mono's for 10 years or so and have run them with several speakers -  2 different sets of Thiels, Eggleston Andra II's and Polk SDA's.  The Eggy's and Mac's were a decent match, not a great match.  They have the same tonal profile thus resulting in over emphasis of certain frequencies, particular on lower midrange and down.  

Thiels and Mac's are a  better match than the Eggy's.  Maybe ideal maybe not.  For comparison sake I also use a Classe CA200 sometimes and they fill up the soundstage with the Thiels better than the Mac's but do not have the full bodied rich sound like the Mac's. They also do not have the clarity of the Mac's.   Everthing is a tradeoff to one degree or another.

I have never owned any other Mcintosh products and have never really considered another one, including preamps.  Not sure about other Mac amps but mine have a 10K input impedance which makes it challenging for many tube preamps to drive.  However, everything considered they are keepers for me, reliable, responsive to other equipment changes, cables and PC's, powerful and rich.  

Your HALO is an excellent unit. MAC has its own sound, which is somewhat euphonic and many people find pleasing.  I would listen head to head at length  before buying.